Battery-driven electronic equipment system and power source control method therefor

ABSTRACT

There is disclosed an electronic equipment system consisting of an electronic equipment and an expander detachably attached thereto and provided with a power source circuit and a power source control circuit in each of the electronic equipment and the expander, the system comprising attachment detecting means for detecting that the expander is attached to electronic equipment, power supply control means for controlling permission or inhibition of power supply to the power source circuit of the other side, other power source control circuit activating means for activating the power source control circuit of the other side by initiating the power supply from the power source circuit of the other side to the power source control circuit of the other side, and informing means for informing the operation status of the power source control circuit of the self side to the power source control circuit of the other side, wherein, in case the attachment detecting means detects the attachment of the expander to the electronic equipment, the power source control circuit of the self side permits the power supply by the power supply control means to the power source circuit of the other side, also causes the other power source control circuit activating means to initiate the power supply from the power source circuit of the other side to the power source control circuit of the other side thereby activating the power source control circuit of the other side, also causes the informing means to inform the operation status of the power source control circuit of the self side to the power source control circuit of the other side, thereby effecting power supply processes synchronized between the both power source control circuits.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an electronic equipment system withdetachable expander and a power source processing method therefor.

2. Related Background Art

Among such electronic equipment system, there has been proposed anotebook personal computer, wherein it's functions can be expanded bydocking an expander incorporating an expansion board.

Such a notebook personal computer with expander is constructed so as toextend the operation time in the portable use, such that it is operableas a dual battery system by extracting the floppy disk drive of thepersonal computer and inserting a second battery.

In recent notebook personal computers, the portability is consideredimportant not only in the state of the notebook personal computer butalso in the state coupled with the expander, so that it is desired toextend the battery-driven time in the state coupled with the expander.

For achieving such extension of the battery-driven time, it isconceivable to employ the second battery of a large capacity or even toemploy a third battery, but, for such purpose, a connection space forthe battery has to be secured on the expander.

FIGS. 21A and 21B show the configurations of the power source in theconventional notebook personal computer, wherein FIG. 21A shows a caseof power supply to the expander from the power source circuit (DC/DCcircuit) of the personal computer, while FIG. 21B shows a case in whichpower source circuits (DC/DC circuits) are respectively provided in thepersonal computer and the expander.

In the case shown in FIG. 21A, the docking connector has to be providedwith power supply lines of a number allowing the supply of a current ofmaximum consumption. Also a signal line for controlling the battery ofthe expander from a power source controlling microcomputer (PMC) has tobe secured in the docking connector. Also the docking connector losesthe compatibility in case the maximum current consumption increases inthe future by the increase of functions of the personal computer or theexpander.

On the other hand, in the configuration shown in FIG. 21B, since theexpander is provided with a power source circuit similar to that in thepersonal computer, the power supply lines can be maintained minimumthough the cost increases by a certain amount. Also this configurationcan flexibly adapt to the increase of the maximum current consumption inthe future. The power source controlling microcomputer (PMC) of thepersonal computer often supports, in addition to the control of thepower source system, other functions such as the keyboard control. Inthe docking, therefore, the power source systems have to be combined soas not to detrimentally affect such other functions. Also the powersource modes of both power source controlling microcomputers have to bemutually synchronized in order to extend the battery-driven time in thedocking state.

SUMMARY OF THE INVENTION

An object of the present invention is to provide an electronic equipmentcapable of docking the power source with an expander unit withoutdetrimental effect on other functions, such as keyboard control,supported by the power source control circuit of the electronicequipment, and a power source control method therefor.

Another object of the present invention is to provide an electronicequipment capable of extending the battery-driven time in the dockedstate by synchronizing the power supply modes of the power sourcecontrol circuits of the electronic equipment and the expander unit, anda power source control method therefor.

The above-mentioned objects can be attained, according to the presentinvention, by an electronic equipment system consisting of an electronicequipment and an expander detachably attached thereto and provided witha power source circuit and a power source control circuit in each of theelectronic equipment and the expander, the system comprising attachmentdetecting means for detecting that the expander is attached to theelectronic equipment, power source control means for controllingpermission or inhibition of power supply to the power source circuit ofthe other side, other power source control circuit activating means foractivating the power source control circuit of the other side byinitiating the power supply from the power source circuit of the otherside to the above-mentioned power source control circuit of the otherside, and informing means for informing the operation status of thepower source control circuit of the self side to the power sourcecontrol circuit of the other side, wherein, in case the attachmentdetecting means detects the attachment of the expander to the electronicequipment, the power source control circuit of the self side permits thepower supply by the above-mentioned power source control means to thepower source circuit of the other side, also causing the above-mentionedother power source control circuit activating means to initiate thepower supply from the power source circuit of the other side to thepower source control circuit of the other side thereby activating thepower source control circuit of the other side, and causing theinforming means to inform the operation status of the power sourcecontrol circuit of the self side to the power source control circuit ofthe other side, thereby effecting power supply processes synchronizedbetween the both power source control circuits.

According to the present invention, there is also provided a powersource control method for an electronic equipment system consisting ofan electronic equipment and an expander detachably attached thereto andprovided with a power source circuit and a power source control circuitin each of the electronic equipment and the expander, wherein, in casethe attachment of the expander to the electronic equipment is detected,the power source control circuit of the self side permits the powersupply to the power source circuit of the other side, also initiatingthe power supply from the power source circuit of the other side to thepower source control circuit of the other side thereby activating thepower source control circuit of the other side, and informing theoperation status of the power source control circuit of the self side tothe power source control circuit of the other side, thereby effectingpower supply processes synchronized between both power source controlcircuits.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1 and 2 are external perspective views of a notebook personalcomputer and an expander;

FIG. 3 is a bottom view of the notebook personal computer;

FIG. 4 is a block diagram showing electrical connection of a core unitand a dock unit;

FIGS. 5 and 6 are circuit diagrams showing electrical connection betweenthe core unit including a one-chip microcomputer H8 and the dock unit;

FIG. 7 is a flow chart showing the entire control sequence executed bythe one-chip microcomputer H8;

FIG. 8 is a flow chart showing the control sequence of an initializationroutine;

FIG. 9 is a flow chart showing the control sequence of a Docking Reset 1routine;

FIG. 10 is a flow chart showing the control sequence of a Docking Reset2 routine;

FIG. 11 is a flow chart showing the control sequence of a PM controlroutine;

FIGS. 12A, 12B and 12C are flow charts showing the control sequence of aSoft Standby transition and a returning process in the undocked state;

FIGS. 13A and 13B are flow charts showing the control sequence of a SoftStandby transition in the docked state;

FIG. 14 is a flow chart showing the control sequence of a returningprocess in the docked state;

FIGS. 15A and 15B are flow charts showing the control sequence of a SoftStandby transition and a returning process of the docking side in thedocked state;

FIG. 16 is a flow chart showing the control sequence of a DOCK_DK*interruption process;

FIG. 17 is a flow chart showing the control sequence of 10 msec cycleprocess in a timer 0 interruption process;

FIG. 18 is a flow chart showing the control sequence of the main routinein a step S3;

FIGS. 19 and 20 are flow charts showing the control sequence of adocking service routine; and

FIGS. 21A and 21B are views showing the power source configurations inconventional notebook personal computers.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Now the electronic equipment system and the power source control methodof the present invention will be clarified by embodiments thereof. FIGS.1 and 2 are external perspective views of a notebook personal computer(hereinafter simply called “computer”) and an expander therefore,respectively in an open state and a closed state of the computer, andFIG. 3 is a bottom view of the computer.

The computer 1 is provided with a display device 10, a keyboard 9, ahard disk drive (not shown), a floppy disk drive 12 etc. The expander 2is provided therein with a CD-ROM drive 13 and an expansion board (notshown) for communication, for sound source etc. In the followingdescription of the present embodiment, the computer 1 will be called acore unit while the expander 2 will be called a docking unit.

On the front faces of the core unit and the docking unit there aremounted intelligent batteries 3C, 3D provided with LED's for indicatingthe remaining battery capacity. At the lateral face of the core unit andon the rear face of the docking unit there are respectively providedinsertion slots 6C, 6D for AC adapters, and between the display unit 10and the keyboard 9 of the core unit there are provided a power switch 11and LED's (not shown) for indicating the status such as informationrelating to the keyboard and the charging status.

At the four corners of the upper face of the docking unit there areprovided hooks 5, 6 for mechanical coupling of the docking unit with thecore unit. The left-side hooks 6 are formed as movable hooks linked witha releasing lever 8. Between the left-side hooks 6 there is provided adocking connector 4 of the docking unit for electrical connectionbetween the core unit and the docking unit. On both sides of the dockingconnector 4, there are provided impingement pins 7.

On the rear face of the core unit there are provided, as shown in FIG.3, engaging holes 15, 16 for engaging with the hooks 5, 6 of the dockingunit, engaging holes 16 for engaging with the impingement pins 7 of thedocking unit, and a docking connecting 4 of the core unit side to beconnected with the docking connector 4 of the docking unit side.

FIG. 4 is a block diagram showing the electrical connection between thecore unit and the docking unit. In each side, there are provided a PClogic system which functions only during the function of a DC/DCconverter (namely only during a power-on state) and a power sourcesystem which always functions as long as a power source is present,regardless of the status of the DC/DC converter, and controls the powersource such as a battery or an AC adapter and the DC/DC converter.

In the present embodiment, a one-chip microcomputer H8 (manufactured byHitachi Mfg. Co.) is employed as the microcomputer for controlling theelectronic elements of the power source system. As shown in FIG. 4, thecore unit and the docking unit respectively have DC/DC converters andhave similar circuit configurations. In this manner it is renderedpossible to reduce the number of signal lines connecting the core unitwith the docking unit and to realize a flexible computer system whichwill not be limited by the power supply in case of future expansion ofthe functions in the core unit or in the docking unit.

FIGS. 5 and 6 are circuit diagrams showing the electrical connectionbetween the core unit and the docking unit with their its one-chipmicrocomputers H8. The one-chip microcomputer H8 of the core unit (CoreH8) and that of the docking unit (Dock H8) have common signals,including output signals HOLDH8 (CRHOLDH8, DKHOLDH8) for securing thepower supply to these microcomputers, output signals PowerFET(ACDCEN/BATEN2/BATEN1) for controlling the electrical connection of theAC adapters or the batteries, input signals (SYSCUR/BATVOLT/BATFCUR) formonitoring the output status of the AC adapter and the charge/dischargestate of the battery, a signal BATCHG for controlling the start andtermination of the charging, an output signal DCON for controlling theDC/DC converter for power supply to the PC logic system, and an inputsignal PGS for confirming the stability of the output.

In the absence of the power source, namely in case of absence of the ACadapter or the battery (including the case of absence of the remainingcapacity), a control signal PLFETEN is released for effecting powersupply from the power source of the other side through a power lineDOCKDC in the docking connector 4.

For recognizing the electrical connection between the core unit and thedocking unit, signals DOCK_DK* and DOCK_CR* are respectively supplied tothe microcomputers Core H8 and Dock H8. The DOCK_DK* signal is generatedby a lever switch positioned close to the releasing lever 8 and assuminga low signal state when the releasing lever 8 is closed (cf. FIG. 5).The signal of the lever switch is also supplied, as an interruptionsignal, to IRQ2* of the microcomputer Dock H8.

Between Core H8 and Dock H8 there are provided power controlling I/Fsignals including a CRT8ACT signal for principally informing the Dock H8of the active/inactive status of the Core H8, a DKH8ACT signal forinforming the Core H8 of the active/inactive status of the Dock H8, anda WAKEUP signal for initiating the power supply to the microcomputer H8of the other side through a H8DC/DC circuit in case the ACT signal ofthe other side is inactive.

The communication between the Core H8 and the Dock H8 is executedutilizing the hardware function incorporated in the microcomputer H8 andaccording to a SMB (system management bus) protocol in an I2C bus of thedocking connector 4. In this communication, the Core H8 always functionsin the master mode while the Dock H8 functions in the slave mode. Thusthe Dock H8 detects the change in the status of the AC adapter or thebattery in the docking unit and releases a signal DKH8IRQ forrequesting, to the Core H8, a communication for acquiring the status.This DKH8IRQ signal also functions as a trigger signal for resetting theCore H8 from the Dock H8 in case the power source of the docking unitside changes in the soft standby state in the docked state. Also atrigger signal CRH8IRQ is provided for resetting the Dock H8 from theCore H8.

The I2C bus of the docking connector 4 is also connected to the battery(battery 2) of the docking unit, so that the Core H8 and the Dock H8 canacquire various information of the battery 2 by the smart batteryfunction. In case the Core H8 acquires the various information from thebattery 1 of the core unit, the bus connection is switched only to thecore unit side by a I2C bus selector control signal I2CSEL in order toprevent the collision of the SMB addresses between the batteries 1 and2.

Also in case the power consumption of the PC logic system increasespossibly beyond the rated power of the AC adapter in the course of thecharging operation in the power-on mode, an ACPL signal is released inorder to urgently interrupt the charging operation.

In the docking connector 4, there is also provided a signal DOCK_PGSsupplied from the Dock H8 to the Core H8 after confirmation of thestable oscillation state of a system DC/DC circuit of the docking unit.This signal is also supplied to the PC logic system to trigger, whenrendered active, the docking sequence of the PC logic system.

For the Core H8 only, there are provided an input signal PWRSR* from thepower switch 11, and a pulse clock signal WKUP2 supplied to the Core H8from a chip set (not shown) of the PC logic system in a suspended mode.

For the Dock H8 only, there is provided a motor controlling outputsignal for an electronic locking mechanism provided in the vicinity ofthe releasing lever 8 for retaining the same in position.

In the following there will be explained the control sequences of theCore H8 and the Dock H8 in the battery-driven state of the computer. Asthe basic functions are common for the Core H8 and the Dock H8 exceptfor certain functions such as the electronic lock control by the DockH8, the following control sequence is common for the Core H8 and theDock H8 unless specified otherwise.

FIG. 7 is a flow chart showing the entire control sequence executed bythe one-chip microcomputer H8. This sequence is executed only one afterthe resetting of the Core H8.

At first there is executed an initialization routine (step S1) forinitialization of the I/O ports, initialization of the internal RAM,setting of interruptions and A/D conversion and initialization of theinternal modules such as I2C. Then executed are a PM (power management)routine for controlling the power supply state of the microcomputer H8itself (step S2) and a main routine for controlling theexecution/nonexecution of the service routines to be explained later(step S3).

The main routine (step S3) can be divided function wise into an I/Oservice routine (step S4) executed at an interval of 10 msec formonitoring various input/output signals, an FET control service routine(step S5) for controlling FET's based on the results of detection in theI/O service routine, a battery control service routine (step S6)executed at an interval of 100 msec principally for controlling thecharging of the battery and detecting the remaining capacity thereof,and a docking service routine (step S7) for executing processes relatedto the power line and the FET's at the docked state.

In response to a request for communication by the DKH8IRQ signal fromthe Dock H8, the Core H8 executes an interruption communication serviceroutine (step S8) for acquiring the interruption right for the Dock H8,according to the SMB protocol. Also while the power supply is turned on(during the power supply to the system from the DC/DC circuit thereof),the Core H8 executes a 8042-compatible keyboard controller serviceroutine (step S9) provided also with a so-called 8051-compatiblefunction (internal keyboard scanning function).

In the present embodiment, there will be given detailed explanation,among the control routines mentioned above, the initialization routine,the PM control routine and the docking service routine which areparticularly closely related to the present invention.

Initialization Routine

FIG. 8 is a flow chart showing the control sequence executed in theinitialization routine. When the user attaches the AC adapter or thebattery 1 to the core unit, a signal CRSTART1 released from a one-shotcircuit of the core unit is rendered active for a period of 50 msec.

The CRSTART1 signal is supplied, through an OR connection with someother signals (a WAKEUP signal and a CRHOLDH8 signal from the Dock H8,to be explained later in the initialization process in the dockedstate), to a CRH8DC/DC circuit, which is activated to effect powersupply to the Core H8 during the active state (50 msec) of the CRSTART1signal. At the same time a CRH8Reset circuit maintains a CH8RST* signalat the low-level state and then it is returned to the high-level state,whereupon a reset sequence of the Core H8 is initiated.

The Core H8 renders a CRHOLDH8 signal active, in order to secure thepower supply to the Core H8 itself after the power supply for 50 msec bythe one-shot circuit. It also renders signals CRACDCEN and CRBATEN1active, thereby tentatively connecting the power source to the CRH8DC/DCcircuit (step S11).

Then, as in the initialization of the ordinary microcomputers, there areexecuted initialization of the stack pointer, the input/outputdirections of the I/O ports and the internal RAM, and initialization ofmodules incorporated in the microcomputer such as A/D conversion,various timer routines, 12C bus routine etc. (step S12).

Particularly in the initialization of the I/O ports, a CRPLFETEN signalfor controlling the power supply from the core unit to the docking unitis set at the low-level non-active state, and the output signals(CR8ACT/CRH8IRQ/DKCHGDIS) connected to the Dock H8 are set at the inputdirection even though they are functionally output signals. Such settingis, as will also be explained later in the docking process, to prevent aleak current generated by the entry of a high-level output signal fromthe Core H8 before the power source voltage is stabilized, in the resetsequence of the Dock H8.

The presence or absence of the AC adapter is confirmed by a CREXACENsignal, and the presence or absence of the connection of the battery 1is judged from the A/D converted value of a signal CRBATVOLT.

If the battery 1 alone is present, the power FET is shifted, from thetentative setting in the step S11, to CRACDCEN (low), CRBATEN1 (high)and CRBATEN (high) (step S14). If the AC adapter is present, thetentative setting of power FET in the step S11 is retained.

The power supply is executed from the AC adapter since it has an outputvoltage of 20 V, while the battery has an output voltage of 16 V atmaximum. In case the AC adapter is extracted, the power supply isswitched to the battery without intervention of the software, so thatthe shut-down of the computer by the disconnection of the power sourcecan be avoided.

In the initialization routine, there is then executed the adjustment ofthe power FET setting according to the connection state of the dockingunit. At first the presence or absence of connection of the docking unitis checked by a DOCK_DK* signal (step S15). If the DOCK_DK* signals inthe high-level state, indicating the absence of docking, the setting ofthe power FET is retained and the sequence branches to a final sequenceof the initialization routine, starting from a step S18 (step S16).

On the other hand, the low-level state of the DOCK_DK* signal indicatesgeneration of resetting in the Core H8 in the docked state, or, morespecifically, a case where the AC adapter or the battery is connected toeither of the core unit and the docking unit which have been in thedocked state without any power source (namely the AC adapted and thebattery are not connected to the core unit and the docking unit).

If the AC adapter and the battery 1 are both unconnected (step S16A),the connection of the power source is made to the docking unit, so thatthe power supply to the core unit is made from the docking unit (theother side) through the FET's d5 and c5, whereby the Core H8 isactivated by the CRH8DC/DC circuit. In this case there is executed aDockingResetl process (step S16B), of which control sequence is shown inFIG. 9.

In this process, the CRPLFETEN signal has a low-level initial value.Since the power supply through the FET c5 is made through a diode and isinefficient, the Core H8 switches the CRPLFETEN signal to the high-levelin order to make direct connection of the power supply line from thedocking unit side to the core unit side (step S17).

The power supplying side judges whether the power supply by the dockingprocess has been successful by a signal ACT from the other side. TheCore H8 switches a CRH8ACT signal, which is directed to the input at theundocked state, to a high-level output signal (step S118) therebyinforming the Dock H8 that the power supply has been successful and thatthe initialization of the Core H8 has been successful, and sets adocking status flag (step S119) which is to be used by other serviceroutines for confirming the docking status.

On the other hand, if the step S16A judges the connection of the ACadapter or the battery 1, the connection of the power source is made tothe core unit which has been without the power source, so that theinitialization process is required to effect the power supply from thecore unit side to the docking unit side. In this case there is executeda DockingReset2 process (step S16C), of which control sequence is shownin FIG. 10.

At first a signal CRBATEN2 is rendered non-active (low-level state) inorder to prevent the current flow into the battery, and then theCRPLEFETEN signal is rendered active (high-level state) to initiate thepower supply from the power source of the core unit to the docking unit(step S120). In this manner there is initiated the power supply to theDKH8DC/DC circuit which the power source circuit for the Dock H8.

Also the WAKEUP signal is rendered active to initiate the power supplyfrom the DKH8DC/DC circuit to the Dock H8. After the lapse of apredetermined time (10 msec) for stabilizing the power source voltage ofthe Dock H8, the ports which have been set for input in the step S12 bythe output signal to the Dock H8 are switched for output (step S121),whereby the DKCHGDIS and CRH8IRQ signals are set at the low-level whilethe CRH8ACT signal is set at the high-level.

The activation of the WAKEUP signal in the step S121 also initiate thepower supply to the Dock H8, whereby a process equivalent to the stepsS11 to S16B in the initialization routine of the Core H8 is executed inthe Dock H8. Within a period of 500 msec, the Core H8 palls if theDKH8ACT signal from the Dock H8 has been switched from the low-level tothe highlevel state (steps S122, S123).

Upon detection of the high-level state of the DKH8ACT signal, there isset a docking status flag (step S124), and the WAKEUP signal which hasbeen rendered active in the step S121 is switched to the non-activestate (step S126).

On the other hand, if the high-level state of the DKH8ACT signal cannotbe detected within the period of 500 msec, the power supply from thecore unit side to the docking unit side or the resetting of the Dock H8is incomplete, so that the Core H8 shifts the CRPLFETEN signal, whichhas been rendered active in the step S120, to the non-active state toterminate the power supply from the core unit to the docking unit andreturns the signals supplied to the Dock H8 to the initialization statein the step S12 (step S125), and the sequence branches to the finalprocess of the initialization routine starting from the step S17.

In case the docking status flag is set at “1”, the 12C bus is switchedto the docking unit side, then a GetPowerSource command is sent to theDock H8 and the initial value of the power source in the docked state isacquired from a returned value (step S17).

In the final process of the intializatio routine, there are executedinitialization of service flags for controlling theexecution/non-execution of various service routines (step S18),initialization (setting at 1 msec) of an H8 internal timer 0constituting a reference timer for periodically executing an I/O serviceroutine, a battery control service routine etc. and permission of atimer 0 interruption (step S19), and setting for an externalinterruption by an external interruption signal such as the DOCK_DK*signal for triggering the execution of a docking service routine to beexplained later or the DKH8IRQ* signal for triggering an interruptioncommunication service routine (step S120), and the sequence thenbranches to the PM control routine in the step 2.

PM Control Routine

The one-chip microcomputer H8 can assume three power supply(normal/sleep/soft standby) modes. For example, for the power source of5 V (10 MHz), the current consumption is 20 mA (normal), 12 mA (sleep)or 0.01 mA (soft standby).

Therefore, in the battery-driven state, namely in a state where the ACadapter is not attached, it is possible to extend the battery-driventime by assuming the soft standby power mode if the power consumption ofthe microcomputer H8 is not negligible in comparison with the powerconsumption of the entire system.

The Core H8 shifts to the soft standby mode in the following two cases:

(1) if the power supply of the system is turned off in thebattery-driven state (off mode soft standby); or

(2) if the system is in the suspended mode in the battery-driven state(on mode soft standby).

In the present embodiment, the suspended mode means a state where theoperation clock signals are not generated for almost all the devices ofthe system and the power supply is stopped to certain devices of highpower consumption such as the display device, whereby the currentconsumption of the system is in the order of 100 mA.

The power-off state is judged in the I/O service routine, by the statusof a CRDCON signal supplied to the core system DC/DC circuit. Also thesuspended mode of the system can be detected by monitoring, in the I/Oservice routine, a signal PC2 which is released from the chip set of thesystem and entered into the external interruption port of the Core H8.

After entering the soft standby mode, the Core H8 recovers therefrom inthe presence of one of the following external interruption signals:

AC adapter presence signal (CREXACEN*);

power switch on signal (PWRSW*);

suspend release signal (PC2*);

PC3 signal (WKUP2);

docking signal (DOCK_DK*);

communication request signal (DKH8IRQ*) from the

Dock H8

These external interruption signals are enabled, depending on theabove-mentioned mode (1) or (2) and on the presence or absence of thedocked state.

If the system is in the docked state at the shifting to the soft standbymode or at the returning therefrom, the communication by the 12C bus maynot be conducted properly if the power mode is not synchronized betweenthe Core H8 and the Dock H8. In the soft standby state, all thefunctions of the one-chip microcomputer H8 are suspended, so that the12C module function cannot be used.

The PM control routine is a service routine for controlling theconditions and the timing of shift and return of the microcomputer H8 toand from the soft standby mode.

FIG. 11 is a flow chart showing the control sequence of the PM controlroutine. At first there is checked the AC adapter flag set in the I/Oservice routine (step S21), and, if the AC adapter is present, thepresent service routine is immediately terminated. This flag indicates,in the undocked state, the presence or absence of the AC adapter in thecore unit, and, in the docked state, the presence or absence of the ACadapter in either of the core unit and the docking unit.

In case the AC adapter is absent, there is checked the valueWAKEUP_COUNT in the internal RAM (step S22), and, if this value is not0, the present service routine is terminated. The value WAKEUP_COUNT isset, in case of generation of an external interruption of a returningfactor in the soft standby state, at the following value according tosuch returning factor:

AC adapter presence signal (CREXACEN*)=10

power switch on signal (PWRSW*)=10

suspend release signal (PC2*)=2

PC3 signal (WKUP2)=2

docking signal (DOCK_DK*) =100

communication request signal (DKH8IRQ*) from Dock

H8=10

For example, the AC adapter flag is not immediately set by the shift ofthe AC adapter presence signal (CREXACEN*) to the low-level state. Inconsideration of the influence of chattering, the AC adapter flag is setonly after the low-level state is detected 5 times in succession (namelyonly if the low-level state is maintained for 50 msec) in the I/Oservice routine.

In case the returning from the soft standby state is triggered by theCREXACEN* signal, a value 10 is set as WAKEUP_COUNT. This value isdecreased by 1 at a cycle time of 10 msec in the timer 0 interruptionprocess executed at an interval of 1 msec, but no longer decreased afterreaching 0. Thus, with the lapse of 100 (10×10) msec after the returningfrom the soft standby state, there is again checked the condition forentering the soft standby state.

In case triggering with the PWRSW* signal, there is similarly secured atime of 100 msec for masking the transition check to the soft standbystate in consideration of the chattering in the I/O service routine.Also in case of the DOCK_DK* signal, there is secured a time of 1000msec for masking the transition check to the soft standby state inconsideration of the process time in the docking service routine to beexplained later. Thus the process of the above-explained step S22 isminimize the operation time in the normal mode respectivelycorresponding to the returning factors, while maintaining the matchingbetween the PM control routine and other service routines.

In case the aforementioned step S22 identifies that the value ofWAKEUP_COUNT is 0, there are checked the status of the CRDCON signal andthat of the PC2 signal fixed in the I/O service routine (step S23), thenthere are discriminated that the power supply is on and that the PC2signal is non-active (step S24), and, if the power supply is on and thePC2 signal is non-active (namely in case the system is not in thesuspended mode), the present service routine is immediately terminated.

Otherwise, there is checked the status of a docking status flag fixed inthe I/O service routine (transition from the docked state to theundocked state) or in the docking service routine (transition from theundocked state to the docked state) (step S24A), and there is executedone of the transitions to the soft standby state in the following fourpatterns, according to the combination of the above-mentioned status andthe status of the AC adapter (steps S24B to S24E):

(1) off-mode soft standby in the undocked state;

(2) on-mode soft standby in the undocked state;

(3) off-mode soft standby in the docked state;

(4) on-mode soft standby in the docked state.

FIGS. 12A to 12C are flow charts showing the sequence of transition toand returning from the soft standby state in the undocked state. Thesystem shifts to the soft standby state, while allowing the externalinterruption by the AC adapter presence signal (CREXACEN*), the powersupply on signal (PWRSW*) or the docking signal (DOCK_DK*) as thereturning factor in the above-mentioned case (1) as shown in FIG. 12A(step S24J) or taking also the suspend release signal (PC2*) or the PC3signal (WKUP2) as the additional returning factors in theabove-mentioned case (2) as shown in FIG. 12B (step S24K).

The transition from the normal mode to the soft standby state isachieved by setting an SSBY bit of a SYSCR register in the internalregister of the one-chip microcomputer H8 and then executing a SLEEPcommand (step S25).

In response the one-chip microcomputer H8 enters a power-saving state inwhich the program execution, the clock signals and the peripheralfunctions are all suspended (step S25A). The recovery from this state isexecuted only by the external interruption, set in the above-mentionedsteps S24J and S24K.

In case any of the above-mentioned returning factor occurs, the one-chipmicrocomputer H8 executes, after a waiting time of about 10 msec by ahold/wait (H/W) function for stabilizing the clock signals, a processcorresponding to such interruption factor as shown in FIG. 12C (stepS26). At the end of the interruption process, there is discriminated, bythe aforementioned SSBY bit of the SYSCR register, if the interruptionis for returning from the soft standby state (step S27), and, if so,there is set a WAKEUP COUNT for each interruption factor (step S28) andthe sequence returns from each interruption process to the PM controlroutine.

Finally the internal modules such as the times 0 and 12C which arestopped during the soft standby state, and the PM control routine isterminated and the sequence is transferred to the main routine (stepS29).

FIGS. 13A and 13B are flow charts showing the sequences of transition tothe soft standby state in the docked state. The system shifts to thesoft standby state, while allowing the external interruption by the ACadapter presence signal, the power supply on signal or the communicationrequest signal (DKH8IRQ*) from the Dock H8 as the returning factor inthe above-mentioned case (3) as shown in FIG. 13A (step S230) or takingalso the PC2 and PC3 signals as the additional returning factors in theabove-mentioned case (4) as shown in FIG. 13B (step S240).

In the soft standby state in the docked state, the synchronization hasto be made with the Dock H8 prior to the transition to such state. TheCore H8 shifts the CRH8ACT signal from the high-level state to thelow-level state (step S241) and awaits that the DKH8ACT signal, suppliedfrom the Dock H8 to the Core H8, is shifted from the high-level state tothe low-level state (step S242). These CRH8ACT and DKH8ACT signals areused as acknowledgment signals for informing the success of the dockingprocess in the aforementioned initialization routine or in the dockingservice routine to be explained later, but, in a state where the dockingis already made, these signals are used as acknowledgment signals forsynchronization of the soft standby state.

In the docked state, the Dock H8 monitors the CRH8ACT signal in the I/Oservice routine. The low-level state of this signal is the condition fortransition to the soft standby state at the Dock H8 side. In response tothe process of the step S241 in the Core H8, the Dock H8 executes, inthe PM control routine, the transition from the normal mode to the softstandby mode.

FIGS. 15A and 15B are flow charts showing the sequences, at the dockingunit side, of transition to and returning from the soft standby state inthe docked state. The sequence allows the external interruption by theAC adapter presence signal (DKEXACEN*), or the communication requestsignal (CRH8IRQ*) from the Core H8 as the returning factor from the softstandby state as shown in FIG. 15A (step S251), then shifts the DKH8ACTsignal from the high-level state to the low-level state (step S252) andshifts to the soft standby mode (steps S253, S254).

In response to the process of the step S252 at the Dock H8, the Core H8detects the shift of the DKH8ACT signal from the high-level state to thelow-level state (step S242) and shifts to the soft standby mode (stepsS243, S244).

FIG. 14 is a flow chart showing the returning process from the softstandby state. In case of the external interruption by any of thereturning factors permitted in the aforementioned steps S230 and S240,an interruption process is executed in a similar manner as in thereturning steps S26, S27 and S28 in the undocked state for achievingshift to the PM control routine (steps S254A, S254B and S254C), and theCRH8ACT signal is shifted from the low-level state to the high-levelstate (step S255).

The returning from the off-mode soft standby state (step S255A) is basedon a change in the status of the AC adapter or of the power source asexplained in the foregoing, and a communication based on the SMBprotocol is executed between the Core H8 and the Dock H8 after thereturning. In such case, the probability of entering the soft standbystate after the returning is very low. Consequently the CRH8IRQ signalis shifted to the high-level state to also recover the Dock H8 from thesoft standby mode (step S256).

The Dock H8 returns from the soft standby state by the inverted inputsignal CRH8IRQ* signal. It returns to the PM control routine bycompleting the interruption process in a similar manner as in the stepsS254A to S254C as shown in FIG. 15B (steps S264A, S264B, S264C), thenshifts the DKH8ACT signal to the high-level state for informing the CoreH8 of return from the soft standby state (step S265), and resets theinternal modules such as the timers 0 and 12C which have been stoppedduring the soft standby mode, thereby terminating the PM control routineand transfers the control to the main routine (step S266).

In response to the process of the step S265 at the Dock H8, the Core H8detects the shift of the DKH8ACT signal to the high-level state (stepS257), then resets the internal modules which have been stopped as inthe Dock H8 (step S258) and terminates the PM control routine.

In the on-mode soft standby state in the docked state in theaforementioned case (4), there is at first discriminated whether thereturning factor is the PC3 signal (step S259), and, if not, there areexecuted the steps S256 to S258 as in the above-explained case (3).

On the other hand, if the returning factor is the PC3 signal (WKUP2),there is executed a special process for extending the battery-driventime. As explained in the foregoing, the PC3 signal is periodicallygenerated in the suspended state, in order to detect the critical levelof the battery in the suspended state and to inform the system of theinitiation of a SaveToDisk process (diversion of the current user workenvironment to the hard disk) based on such detection. These processesare executed in the I/O service routine.

The critical level of the battery is to be detected by the intelligentbattery itself, but, since the remaining capacity obtained from thebattery may contain accumulated errors, the present embodiment improvesthe reliability by executing the critical level detection based on theA/D converted values of the voltage and the current of the battery.

On the other hand, the remaining battery capacity decreases verygradually if the suspended state is continued in the battery-drivenmode. After the critical battery levels is checked in the I/O serviceroutine, the system again shifts to the soft standby mode in most cases,even without communication with the Dock H8.

Since the normal mode and the soft standby mode are significantlydifferent in the electric power consumption, the duration of thesuspended state will become limited if the Dock H8 is unnecessarilyreturned from the soft standby state in the docked state. Therefore, thepresent embodiment adopts control to minimize the returning of the DockH8 from the soft standby state for the critical battery level.

In case the step S259 identifies that the returning factor is the PC3signal, the control is switched according to the connection status ofthe battery FET. The Core H8 know the status of all the FET's of thecore unit and the docking unit, by an FET control service routine.

If the power supply may be made from the battery 2 of the docking unit,namely in case DKBATEN1=Hi (step S260), a PC3WAKEUP_COUNT area of theinternal RAM is used to branch, after a count of 30, to a process forthe off-mode soft standby state, thereby returning also the Dock H8 fromthe soft standby mode (step S261).

In this manner the Core H8 returns from the soft standby state for aperiod of 20 msec in every 2 seconds, but the Dock H8 returns from thesoft standby state only for a period of 20 msec in every 60 seconds.

If the power supply is not made from the battery 2 of the docking unit,namely if DKBATEN1=Low, the operations are solely made by the battery 1of the core unit, so that the periodical check of the remaining batterycapacity is not necessary in the Dock H8 side. Consequently, as in theundocked state, there are reset the internal modules which have beenstopped (step S262) and the PM control routine is terminated. The DockH8 does not return from the soft standby state even when the returningfactor by the PC3 signal is generated.

Docking Service Routine

The basic control of the docking service routine is similar to that ofthe initialization process when the AC adapter or the battery 1 isconnected to the core unit while the core unit and the docking unit lackthe power source in the docked state.

The only difference lies in a fact that other service routines are notyet executed in case of the initialization process but such otherservice routines have already been executed in case of the dockingservice routine. Such other service routines include, for example, thebattery control service routine and the keyboard controller serviceroutine if the power supply is turned on.

At first there will be explained a pre-process prior to the execution ofthe docking service routine. FIG. 16 is a flow chart showing a DOCK_DK*interruption process, which is executed when the DOCK_DK* signal isrendered active. There is discriminated, by the SSBY bit of the SYSCRregister in the internal control register, whether the returning fromthe soft standby state is intended (step S71).

If the SSBY bit is 1, indicating the returning from the soft standbystate, there is set a value 100 in a work area of the WAKEUP_COUNT inorder to mask the next transition to the soft standby state as alreadyexplained in the PM control routine (step S72), and there is set adocking service execution request flag which is to be referred to in atimer 0 interruption process to be explained later (step S73), whereuponthe DOCK_DK* interruption process is terminated.

On the other hand, if the SSBY bit is 0, there is only executed thesetting of the docking service execution request flag and the DOCK_DK*interruption process is terminated.

FIG. 17 is a flow chart showing a 10 msec cycle process in the timer 0interruption processes. The timer 0 interruption processes includes a 1msec cycle process, a 10 msec cycle process, a 100 msec cycle processetc. In the 10 msec cycle process, which is executed once for every 10entries of the type 0 interruptions, there is discriminated whether thevalue of WAKEUP_COUNT is 0 (step S74), and, if not, this value isdecreased by 1 (step S75).

Then there is checked the docking service execution request flag (stepS76), and, only if the flag is 1, there is set a docking service requestflag which is to be referred to in the main routine (step S77). Thedocking service execution request flag is cleared in a final sequence ofthe docking service routine to be explained later.

FIG. 18 is a flow chart showing the process of the step S3 in the mainroutine. In the main routine, there are checked the states of the flags(steps S171, S173, S175, S177), and, if the docking service request flagis set (step S175), the flag is reset (step S176) as in the cases offlags for other service routines (steps S172, S174, S178) and thedocking service routine is called (step S7). Subsequently the sequencereturns to the checking of the service request flags. In FIG. 18 thereare only shown the I/O service routine, the battery control serviceroutine, the docking service routine and the keyboard controller (KBC)service routine.

The above-explained steps S71 to S77, S176 and S7 allow to execute thedocking service routine at an interval of 10 msec until the completionof the docking process, without detrimental effect on other serviceroutines, in case the user combines the core unit and the docking unitand closes the releasing lever 8.

FIGS. 19 and 20 are flow charts showing the control sequence of thedocking service routine, which consists of sequences of 4 levels, namelythe tentative FET setting, the power line setting and activation of theone-chip microcomputer H8 of the other side, the output of an ACT signaland palling of the ACT signal of the other side, and the final process.These sequences are respectively defined as Nos. 0, 1, 2 and 3 and arestored in the work area of the internal RAM.

At first there is checked the sequence number (step S78), and, if thenumber is 4 or larger, the sequence branches to a step S79 to beexplained later, whereby the present service routine is terminated.

If the sequence number is 0, indicating the first routine after theDOCK_DK* signal is rendered active, the DOCK_DK* signal is re-checked(step S81). If it is non-active, indicating an improper DOCK_DK*interruption for example by a noise or a chattering of the releasinglever 8, the docking service execution request flag and the sequencenumber are reset (steps S79, S80) and the docking service routine isterminated.

On the other hand, if the step S81 identifies that the DOCK_DK* signalis active, the CRBATEN2 signal is shifted to the low-level state inorder to avoid current flowing from the battery 2 to the battery 1through the power line (step S82), then the sequence number is shiftedfrom 0 to 1 (step S83) and the docking service routine is terminated.

If the sequence number is 1, the CRPLFETEN signal is rendered active(Hi) (step S84) to initiate the power supply from the power source ofthe core unit to the docking unit. In this manner there is initiated thepower supply to the DKH8DC/DC circuit, constituting the power sourcecircuit for the Dock H8.

Also the WAKEUP signal is rendered active in order to initiate the powersupply from the DKH8DC/DC circuit to the Dock H8 (step S85), then acount 50 (500 msec) is set, for a next sequence, in a counterActTimeOut_Count for counting the waiting time for the ACT signal of theother side (step S86), then the sequence number is switched from 1 to 2(step S87) and the docking service routine is terminated. The process ofthe sequence No. 1 is not particularly meaningful in case the dockingunit has the power source, but does not detrimentally affect the dockingsequence.

If the sequence number is 2, the ports that have been set for input bythe output signal to the Dock H8 in the step S12 of the initializationprocess are switched to output (step S88). The DKCHGDIS and CRH8IRQsignals are set at the low output state while the CRH8ACT is set at thehigh output state.

Then there is checked the DCH8ACT signal, which is the ACT signal fromthe Dock H8 (step S89), and, if it is in the low-level state, the valueof the ActTimeOut_Count is decreased by 1 (step S92), but, if it is not0 (step S93), the docking service routine is terminated.

In case of value 0 (step S93), namely in case the ACT signal from theDock H8 is not switched from the low-level state to the high-level stateafter the lapse of 500 msec from the activation of the Dock H8 by theWAKEUP signal, an error process is executed to disconnect the power linewhich has been connected in the step S84, to return the setting of thestep S88 to that in the undocked state and to shift the WAKEUP signal tothe low-level state (step S94).

Then the docking service execution request flag and the sequence numberare reset (steps S95, S96) and the docking service routine isterminated.

In case the high-level state of the DKH8ACT signal is detected in thestep S89 by within 50 checks of this signal, namely in case theactivation or the docking of the Dock H8 is achieved in normal manner,the WAKEUP signal rendered active in the step S85 is switched to thenon-active state (step S90), then the sequence number is shifted from 2to 3 (step S91) and the docking service routine is terminated.

The process up to the sequence number 2 confirms that the Core H8 andthe Dock H8 are on a substantially same sequence, namely that they havecompleted the initialization process and have moved to the main routine.Consequently the exchange of commands through the 12C bus is completelyassured thereafter.

If the sequence number is 3, at first a command for acquiring the statusof the power source of the docking unit is sent, through the 12C bus, tothe Dock H8 (step S94A), and an optimum state of the power FET iscalculated from the value returned from the Dock H8 and indicating thestatus of the power source of the docking unit side and the status ofpower source of the core unit obtained in the I/O service routine (stepS95A).

This calculation is conducted by a table search, based on the presenceor absence of the power source in the core unit and in the docking unitand on the remaining capacities of the batteries. The set value of thepower FET of the docking unit, calculated by the table search, isinformed by a command to the Dock H8 (step S96A), and the power FET ofthe core unit is switched from the state tentatively set in the step S82to the setting calculated by the table search (step S97).

Then there is checked the status of the CRDCON signal which is theoutput signal to the system DC/DC circuit controlled in the I/O serviceroutine (step S98), and, if the CRDCON signal is in the high-levelstate, a DockDCDCOn command for activating the system DC/DC circuit ofthe docking unit is transmitted to the Dock H8 through the 12C bus (stepS99), then there is set a docking status flag for informing thecompletion of the docking service to other service routines (step S100),and the docking service execution request flag and the sequence numberare reset (steps S101, S102) to complete the docking service routine. Inthis manner the docking service routine is completely terminated.

In the docking process of the system logic side, the Dock H8, inresponse to the DockDCDCOn command in the step S99, activates the systemDC/DC circuit of the docking unit, also controls the DC motor for thereleasing lever 8 so as to fix the same and supplies the core unit witha DOCK_PGS signal for executing the configuration of various logicdevices of the docking unit in the BIOS SMI process.

As explained in the foregoing, the present invention enables couplingwith the expander unit without detrimental effect on other functions,such as the keyboard control, supported by the power source controlcircuit of the electronic equipment.

What is claimed is:
 1. An electronic equipment system, comprising:electronic equipment including a first power source and a first controlpart for controlling said first power source; an expander detachablyattached to said electronic equipment, said expander including a secondpower source and a second control part for controlling said second powersource, wherein the electronic equipment includes informationtransmission means for transmitting information between said firstcontrol part and said second control part; power transmission means fortransmitting power between said electronic equipment and said expander,wherein power is transmitted or received through said transmission powermeans in accordance with the information.
 2. An electronic equipmentsystem according to claim 1, further comprising a first switching meansand a second switching means for enabling or disabling said powertransmission means, wherein said first control part controls said firstswitching means and said second control part controls said secondswitching means.
 3. An electronic equipment system according to claim 1,wherein said electronic equipment further comprises a first judgementmeans for judging whether or not an AC adapter is connected thereto; andwherein said expander further comprises a second judgement means forjudging whether or not an AC adapter is connected thereto.
 4. Anelectronic equipment system according to claim 1, said electronicequipment further comprising connection judgement means for judgingwhether or not said expander is connected thereto.
 5. An electronicequipment system according to claim 2, wherein said electronic equipmentdesignates said expander to turn said second switching means on and saidexpander turns said second switching means on in accordance with saiddesignation.
 6. An electronic equipment system according to claim 4,wherein said connection judgement means detects whether said expander isattached to said electronic equipment.
 7. An electronic equipment systemaccording to claim 6, further comprising switching means for turningsaid power means on or off, wherein said electronic equipment transmitsdesignation information to said expander when said connection judgementmeans detects that said expander is attached to said electronicequipment, and wherein said second control part turns said switchingmeans on in accordance with the designation information.
 8. Anelectronic equipment system according to claim 1, wherein said firstcontrol part controls operation modes of said electronic equipment andsaid expander.
 9. A power transmitting method of an electronic equipmentsystem including electronic equipment and an expander detachablyattached to the electronic equipment, wherein the electronic equipmentincludes a first power source and a first control part for controllingthe first power source, and wherein the expander includes a second powersource and a second control part for controlling the second powersource, said method comprising the steps of: transmitting informationbetween the first control part and the second control part; andtransmitting power between the electronic equipment and the expander inaccordance with the information.
 10. A method according to claim 9,further comprising a first switching step and a second switching stepfor enabling or disabling power transmission, wherein the firstswitching step is performed by the first control part and the secondswitching step is performed by the second control part.
 11. A methodaccording to claim 9, further comprising the steps of: a first judgmentstep for judging whether or not an AC adapter is connected to theelectronic equipment; and second judgment step for judging whether ornot an AC adapter is connected to the expander.
 12. A method accordingto claim 9, further comprising a connection judgement step for judgingwhether or not the expander is connected to the electronic equipment.13. A method according to claim 10, wherein the electronic equipmentdesignates the expander to transmit power in the second switching stepand the expander transmits power in the second switching step inaccordance with said designation.
 14. A method according to claim 12,wherein it is detected in the connection judgement step whether theexpander is attached to the electronic equipment.
 15. A method accordingto claim 14, further comprising a switching step for enabling ordisabling power transmission in said power transmission step, whereindesignation information is transmitted to the expander by the electronicequipment when it is detected that the expander is attached to theelectronic equipment in said connection judgement step, and wherein theswitching step is performed by the second control part in accordancewith the designation information.
 16. A method according to claim 9,further comprising a step of controlling operation modes of theelectronic equipment and the expander by the first control part.